I wish we could see your spreadsheet ( you could try and set it up as the rest of us do this are the instructions
http://www.felinediabetes.com/FDMB/threads/fdmb-spreadsheet-instructions.130337/) and try to see a little bit more information, is hard to give anything but general suggestions with out information.
But for what you have told us what I understand is that because of your schedule you have been changing shooting times and doses a lot, and unfortunately that is not how Lantus works, Lantus requires consistency for it to work properly, that is keep the same dose for a week unless he goes under 90 ( this is following the SLGS protocol ) and the 12 hour shooting schedule as close as possible.
I strongly suggest you take a look at the information on Lantus (
http://www.felinediabetes.com/FDMB/...the-basics-new-to-the-group-start-here.18139/ ) and specially on the Start Low Gow Slow Protocol (this is the link
http://www.felinediabetes.com/FDMB/threads/lantus-levemir-start-low-go-slow-method-slgs.129446/) and maybe go with a very conservative approach in order to keep him safe and try and start as if he hadn't had any insulin with the 0.5 units starting dose that the protocol suggests, try and keep it for a week ( you can ask for help anytime during that period ) and do a curve by the end of the week ( you could ask for help on this one too before doing it) and then post here for a suggestion on how to adjust his dose.
Still you do need to test before shooting ( this could really save his life )and withdraw food 2 hours before his preshoot test to get a test that is not food influenced.
As I said before I do know that following the protocol with a full time job is complicated but it can be done and all the effort and complications are worthed once you see him ok and regulated.
Keep asking as much as you need we will try to help you as much as possible